28751989 has 4 divisors (see below), whose sum is σ = 32859424. Its totient is φ = 24644556.

The previous prime is 28751977. The next prime is 28752007. The reversal of 28751989 is 98915782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28751989 - 2¹⁵ = 28719221 is a prime.

It is a super-2 number, since 2×28751989² = 1653353742912242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28751929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2053707 + ... + 2053720.

It is an arithmetic number, because the mean of its divisors is an integer number (8214856).

Almost surely, 2^28751989 is an apocalyptic number.

It is an amenable number.

28751989 is a deficient number, since it is larger than the sum of its proper divisors (4107435).

28751989 is an equidigital number, since it uses as much as digits as its factorization.

28751989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4107434.

The product of its digits is 362880, while the sum is 49.

The square root of 28751989 is about 5362.0881193804. The cubic root of 28751989 is about 306.3533482102.

The spelling of 28751989 in words is "twenty-eight million, seven hundred fifty-one thousand, nine hundred eighty-nine".